Embodiments of the invention relate to a subrack for the installation of electronic cards with a standardized circuit board format (e.g., according to the PICMG-Standard Advanced Telecom Computing Architecture (“ATCA”)) for powerful communications servers.
In some configurations, if a relatively large number of circuit boards with many electronic components or modules is packed into a relatively small subrack, a relatively large amount of heat may have to be dissipated from the electronic circuit boards. Accordingly, heat management may be of particular importance for these and other systems. As one example, according to the specification PICMG 3.0, up to 450 watts per ATCA-board are allowable, which corresponds to more than 6 kilowatts of heat that needs to be dissipated in a subrack with 14 slots.
In some configurations, an ATCA-subrack can include electric fans, which are located below or above the installation space. Cool air from the environment can be thereby sucked-in through openings at the front of the rack and guided into the installation space, where it passes by the electronic circuit boards, in order to cool them. The resulting heated-up air can be subsequently blown out through openings at the back of the rack. In conventional arrangements, the electric fans can be combined into one horizontal fan tray, which can be pulled out of the rack for maintenance and repair purposes.
In some cases, an appropriately powerful ventilation system, including the associated air distribution components, can require a lot of space within a particular subrack. This can correspondingly limit the space that remains for the installation of electronic circuit boards, especially with regard to the actually usable height.
Further, in some conventional arrangements, server systems that include a number of electronic circuit boards and fans or fan trays for cooling can be supplied with electrical energy by means of separate sub-assemblies or modules. For example, power supply units (“PSUs”) can supply the entire system with power, wherein the operating voltages can be continuously measured and monitored, in cooperation with one or more shelf managers. Such PSUs, which can be implemented with multiple redundancy for larger systems, may demand additional space, in particular height, which in turn may not be available as installation space for electronic cards.
U.S. Pat. No. 8,514,571 B2 describes a subrack for a horizontal mounting of electronic boards (i.e., a horizontal subrack). A ventilation box is arranged above and below an installation space for circuit boards. This box is divided by a partition wall into a right and a left chamber, in particular an air intake chamber for cool air intake and an air outlet chamber for heated exhaust air. An air intake for cool air is provided on the front side, and an air output for heated up waste air is provided on the rear panel. A fan unit with several electric fans is located behind the air intake. Air chambers are provided on the right and left side of the installation space, in particular an air distribution chamber for incoming cold air and an air collecting chamber for heated up air. These air chambers are connected to the intake chamber or to the outlet chamber of the ventilation box. Fresh air from the environment can thus be sucked in through the intake and be pushed downwards into the air distribution chamber. The cold air is deflected at a 90 degree angle into the horizontal direction, flows throughout the installation space and accumulates as heated up air in the air collecting chamber on the other side. From there the hot air is pushed upwards into the air outlet chamber and finally escapes through the air outlet into the surrounding environment.